Plastic ABS (bulk/injection) vs. Stainless 17-4PH

Compare Plastic ABS (bulk/injection) vs. Stainless 17-4PH strength, stiffness, weight and thermal properties.

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Plastic ABS (bulk/injection)Bulk polymer (molded or machined)

Mechanical
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Yield strength	45MPasourcetypical, tensile stress at yield 23 °C	1,275MPasourcetypical, transverse, sheet/strip
Ultimate tensile strength	not sourced	1,379MPasourcetypical, transverse, sheet/strip
Flexural strength	65MPasourcetypical, 23 °C	not sourced
Elongation at break	10%sourcenominal strain at break, 23 °C	9%sourcetypical, transverse, in 2 in. (50.8 mm)
Young's modulus (stiffness)	2.3GPasourcetypical	197GPasourceH 900
Density	1,040kg/m³sourcetypical	7,800kg/m³sourceH 900
Strength to weight	43.3kN·m/kg	163kN·m/kg3.78x higher
Stiffness to weight	2.21MN·m/kg	25.3MN·m/kg11.4x higher
Poisson's ratio	0.39sourcetypical, ABS family (Covestro Part and Mold Design guide, Table 3-1)	0.272sourceH 900 (column)
Shear modulus	0.827GPa	77.4GPa93.6x stiffer in shear
Bulk modulus	3.48GPa	144GPa
Speed of sound	1,487m/s	5,026m/s
Thermal
Thermal conductivity	0.17W/m·Ksourcetypical	17.9W/m·Ksourceat 149 °C (300 °F), H 900
Thermal expansion	80–110µm/m·Ksourcerange	10.8µm/m·Ksourcemean, 21–93 °C (70–200 °F), H 900
100 mm part over a 50 °C swing	475µm growth	54µm growth8.8x less
Specific heat	not sourced	460J/kg·Ksourcemean, 0–100 °C, H 900
Heats up and cools (diffusivity)	not sourced	4.99mm²/s
Thermal shock resistance	21.4W/m	7,809W/m366x more resistant
Max service temperature	94°CsourceHDT 1.8 MPa (annealed 4 h/80 °C)	316°Csourcestrength-retention limit (not oxidation)
Values for	INEOS Styrolution Terluran GP-22 general-purpose injection-molding ABS, ISO typical values (TDS revision 08/01/2022)	Cleveland-Cliffs 17-4 PH, Condition H 900, sheet/strip, transverse (Product Data Bulletin, May 2021)

Every value links to the document that states it. "Not sourced" means no citable source states it (or only a specification minimum); figures computed from it are left out too.

Questions

Is Plastic ABS (bulk/injection) stronger than Stainless 17-4PH?

Stainless 17-4PH is stronger: its yield strength is 1,275 MPa against 45 MPa for Plastic ABS (bulk/injection) (28.3x).

Which is lighter, Plastic ABS (bulk/injection) or Stainless 17-4PH?

Plastic ABS (bulk/injection) is lighter: 1,040 kg/m³ against 7,800 kg/m³ for Stainless 17-4PH.

Which is stiffer, Plastic ABS (bulk/injection) or Stainless 17-4PH?

Stainless 17-4PH is stiffer: Young's modulus 197 GPa against 2.3 GPa for Plastic ABS (bulk/injection), so the same part in Stainless 17-4PH deflects less under the same load.

Which is lighter for the same job, Plastic ABS (bulk/injection) or Stainless 17-4PH?

For the same stiffness or strength: Plastic ABS (bulk/injection) is lighter for a stiff panel or plate, strong panel or plate; Stainless 17-4PH is lighter for a stiff rod or tie (tension), stiff beam (bending), strong rod or tie, strong beam.

Part that must be	Plastic ABS (bulk/injection)	Stainless 17-4PH
Stiff rod or tie (tension)	11.4x heavier	lighter
Stiff beam (bending)	23% heavier	lighter
Stiff panel or plate	lighter	1.7x heavier
Strong rod or tie	3.78x heavier	lighter
Strong beam	24% heavier	lighter
Strong panel or plate	lighter	41% heavier

For the same stiffness or strength, mass scales with density over stiffness (or strength) raised to a power set by how the part is loaded: 1 for a rod in tension, 1/2 for a beam in bending, 1/3 for a panel (the standard material-selection indices).

Which conducts heat better, Plastic ABS (bulk/injection) or Stainless 17-4PH?

Stainless 17-4PH conducts heat better: 17.9 W/m·K against 0.17 W/m·K for Plastic ABS (bulk/injection).

Which expands less with temperature?

Stainless 17-4PH expands less: 10.8 µm/m·K against 95 µm/m·K for Plastic ABS (bulk/injection).

Among 59 materials

Stiffness against density

Strength against density